cacosh, cacoshf, cacoshl − complex arc hyperbolic cosine

#include <complex.h>

double complex cacosh(double complex z);

float complex cacoshf(float complex double z);

long double complex cacoshl(long double complex z);

The cacosh() function calculates the complex acosh(). If y = cacosh(z), then z = ccosh(y). The imaginary part of y is chosen in the interval [-pi*i,pi*i]. The real part of y is chosen nonnegative.

One has cacosh(z) = (0.5)*clog((1+z)/(1-z)).

C99

cabs(3), cimag(3), acosh(3)